Memory champion Katie Kermode … ‘Despite being able to memorise names really well in competitions, I do forget them in real life.’
Photograph: Lorne Campbell/Guzelian

Alex Mullen has an extraordinary talent: after just 16 seconds of flicking through a pack of cards, he can recall their exact order. The 26-year-old medical student began using memory techniques to help with his university degree, but he picked them up so quickly that soon he was entering competitions, eventually becoming the International Association of Memory world champion in 2015. At the championships, which take place again this December, “memory athletes” compete to remember the most in the shortest time, in categories that include card sequences, names, faces and dates of historic events.

“My first world championships win was very surreal. I was training hard, but winning was never really on my radar,” Mullen says. “When I won by literally one second, on the tenth and final event, I didn’t really process it.” Yet he went on to win the championships again in 2017, is ranked No 1 in the world and holds multiple records for his recall skills.

People like Mullen raise important questions in a world where digital databases, whose powers of retention are far greater than our own, are increasingly standing in for human memories. If we no longer need to keep a mental note of facts, figures or dates, might we lose our ability to retain information?

We know that the brain is malleable. A study in 2000 showed that the hippocampus, a region of the brain that plays an important role in memory, was larger in London cab drivers than in the wider public, perhaps because they had to learn and retain the “knowledge” – the quickest routes through the capital’s streets.

Emma Ward, a senior lecturer in psychology at Middlesex University, says that the internet hasn’t been an integral part of our lives for long enough for scientists to fully comprehend its long-term effect on people’s brains. She adds: “There is evidence that memory training is beneficial – and the very idea behind this is practice and rehearsal, so that neural pathways become strengthened.

“One may argue that the more we become reliant on memory aids and technology as reminders, the less efficient our memory processes become. It will be interesting, in years to come, to examine children who grew up with such available technology, to see the effect it has upon memory and cognition.”

Dean Burnett, a neuroscientist and author, believes that memory needs to be exercised. “It is a biological function, like most others, and so not using it would mean it’s less robust and less reliable than in someone who uses it often,” he says. “Memories are essentially connections between neurons, and it is widely agreed that, to keep these connections intact, they have to be ‘activated’ regularly. Retrieving a memory activates it.” Yet he cautions against the idea that we are “losing” our memories because we have outsourced them: “It’s not that they fade away, degrade or anything like that; it’s just that our brains struggle to find them if they are seldom used.”

Technology may affect us in more subtle ways, Ward believes. She cites a study in which participants who were shown a faked photo of themselves as children in hot-air balloons later “recalled” the nonexistent event. “Memories are not like filing cabinets,” she says. “Our brains adapt a lot of what we experience so that we can make sense of the world around us, and our memories are quite often representations or distortions of reality. Being bombarded with vast amounts of information and photos online may create what we call false memories.”

Being able to capture your holiday entirely on a smartphone is convenient, for instance, but experiments have suggested that if you are doing this, you are not paying attention to your environment. If you are distracted, neural pathways in the brain are not being exercised in a way that would strengthen the memory, leaving it vulnerable to distortion.

It is not all bad news when it comes to our reliance on Google and co, though. Other studies have shown it could benefit short-term memory and problem-solving. Gary Small, a professor of psychiatry and biobehavioural sciences at UCLA, compared the brains of “internet naive” and “internet savvy” older adults and found that neural activity increased among the naive group after they had spent a week searching for things online. “We saw significant increases, particularly in the frontal lobe – the thinking brain, the part of the brain that controls working memory.”

He believes that this study shows that people can develop cognitive efficiency, and likens the memory to muscles. “It’s similar to what happens if you work out at the gym. At first, it takes a lot of energy to lift weights, but with training you can lift a lot more weight and exert less energy.”

If you feel the need for some of this training, the memory athletes say that anyone can learn their techniques. Mullen says that before he was breaking world records, he had an average memory. That started to change after he read Moonwalking With Einstein, Joshua Foer’s book about his attempt to become the US memory champion. “You need to do a lot of practice,” Mullen says. “It just depends on how much you’re willing to put into it.”

The most common technique used by memory athletes is the “method of loci”, better known to fans of the TV series Sherlock as the “memory palace”. The idea is that when memorising a list – such as a to-do list – you associate an image with every item on it. The images, which can be as absurd as you like, are then placed in the rooms in your “palace”, which will typically be your home or another familiar building. To recall the list, you imagine walking from one room to the next.

Katie Kermode, from Cheshire, holds two world records: for memorising 105 names and faces in five minutes and for memorising 318 random words in 15 minutes. “I have a journey that goes around my house and other houses I have lived in,” she says. “I put two words in each room and I just associate those two words in a visual way. Then I walk back in my head through the different routes and I remember which words I saw.”

Boris Nikolai Konrad, a Netherlands-based neuroscientist who is also a record-breaking memory athlete, says he has “60 or 70” memory palaces. “One is on the Thames in London, one is at Buckingham Palace and one is my former student house in Reading,” he says. But he uses a different technique to memorise long strings of numbers, creating an image for every two digits in what is known as a person-action-object mnemonic. The number 19, for example, could be represented by a giraffe (the “person”) eating (the action) leaves from a tall tree (the object). As one image follows another, a story or journey builds up, which helps somebody to recall the whole long series of numbers.

Mullen uses a similar device, only with each image representing three digits. He asks me to provide him with six random digits. I offer 876518. “For me, 876 is like a large palm tree – a classic palm tree that you’d see on a beach,” Mullen says. “And 518 is a Twinkie [a popular American snack]. So the trunk of the palm tree is all made out of Twinkie, all the coconuts are weighing down on the trunk and the creamy filling is spilling out.”

Yanjaa Wintersoul, usually known as Yanjaa, is a Mongolian-born Swedish memory athlete based in New York, and is one of the more exciting figures in a sport that is hardly spectator-friendly. (“It’s a bit like a school exam with everyone sitting at their desks staring at paper,” is how Konrad describes the championships.)Like Mullen, Yanjaa was initially drawn to memory competitions after reading Moonwalking With Einstein. Yet she believes the techniques can help in other areas. “At the beginning, it feels elaborate and complicated, but in the end, it’s automatic and faster than anything you can possibly do any other way,” she says. “People see this as a wacky party trick, but the truth is it’s so helpful for mental health and focus.”

She has seen that at first-hand. “In my case, the battle was with depression and anxiety. During the memory training, you’re spending all your time thinking about happy things – if you choose your imagery correctly.”

With the right approach, even Kermode’s five-year-old can memorise shopping lists. “If the first item on the list is bread, I tell her to imagine that on her head,” Kermode says. “The next item, she imagines on her eyes, the next one, on her nose … and you just work down the list. When we get to the shop, she can tell me what we went to the shop for.”

That must make visiting the supermarket more fun. But do the memory champions’ techniques help in more profound ways? Would we all benefit from retraining our brains? Burnett isn’t convinced. “It doesn’t actually help you understand anything,” he says. “It just helps you remember things. If you do crosswords every day, then you will become very good at doing crosswords. That doesn’t mean your brain has improved; it just means your brain is now good at doing crosswords because it has the ability to specialise like that.”

The neuroscientist Susan Greenfield argues that children should be taught to join up the dots rather than just recall them. She asks: “What is more important? Remembering the date of a battle, or understanding why the battle is important? We mustn’t confuse those quick memory tricks with understanding. If you understand something, you don’t have to make an effort to understand it – it’s just there.”

Even the memory champions admit their hard-earned abilities have their limits. Mullen and Kermode say that if they don’t practise some of their skills, they begin to fade with time – and they still regularly have lapses in memory. “Despite being able to memorise names really well in competitions, I do forget them in real life,” Kermode says. “The other day, I not only forgot the name of someone I met, I also wasn’t sure if it was even the same person.”

Still, there is one benefit that even the sceptics can’t quibble about. “Memory training has helped me remember where I put my keys much faster,” says Yanjaa.

• This article was amended on 13 November 2018 to make it clear that the five-year-old mentioned was Katie Kermode’s daughter.